Sputtering of theMartian atmosphere by solar wind pick-up ions
نویسندگان
چکیده
Monte Carlo models are used to describe the interaction between the incident pick-up ions and the Mars neutral atmosphere. The sputtered population inside the corona and escaping particles are described using a modi4ed 3D test particle model, whereas, the heating e6ect due to the incident 7ux is described using a 2D Direct Simulation Monte Carlo. These results show that the standard 1D models overestimate the sputtering yield (by 15–25%), when corrected for coronal ejection. It is also shown that the exobase altitude can depend on sputtering. Two epochs of Mars history are simulated. For an epoch suggested to be about 2.5 Gyr ago, sputtering is at least as important as dissociative-recombination for populating the corona and the heating due to the pick-up ion 7ux is of the same order as the EUV and UV heating of the thermosphere. For this epoch and present solar minimum conditions we present the distribution in the density and the energy of the sputtered particles in Mars corona. In particular we show that the polar and dusk regions are the most dense regions and the shadow of the dawn and polar regions the most energetic regions. c © 2001 Elsevier Science Ltd. All rights reserved.
منابع مشابه
The Physics and Chemistry of Sputtering by Energetic Plasma Ions
Energetic ions from the solar wind, local pick-up ions or magnetospheric plasma ions impact the atmospheres and surfaces of a number of solar system bodies. These energetic incident ions deposit energy in the gas or solid. This can lead to the ejection of atoms and molecules, a process referred to as sputtering. In this paper we first describe the physics and chemistry of atmospheric and surfac...
متن کاملAtmospheric Escape at Mars
Introduction: Several mechanisms have been identified to result in escape of the Martian atmosphere. These mechanisms can be divided in two groups [1]: • Thermal escape or Jeans escape, which corresponds to the loss of atoms in the high energy tail of the energy distribution at the exobase. This mechanism is important only for the light species such as hydrogen or deuterium. • Non-thermal escap...
متن کاملLunar Surface' Sputtering and Secondary Ion Mass Spectrometry
We combine laboratory and Apollo year on the moon) every surface species has been observations to describe the sputtering of the struck and subsequent ions eject chemicallylunar surface and the composition of the ejecta altered species. At high fluences sputtering with special reference to O. The atmospheric proceeds stoichiometrically (Johnson 1990). inventory appears to be dominated by microT...
متن کاملObservational Test for the Solar Wind Sputtering Originof the Moon’s Extended Sodium Atmosphere
We present observations of the lunar sodium atmosphere during four lunar eclipses between 1993 and 1997. With the Moon inside the magnetosphere, and therefore shielded from solar wind impact, we find its Na atmosphere to be comparable in abundance to cases near first and third quarter, implying that solar wind ion sputtering is not a significant source of the atmosphere. The atmosphere is azimu...
متن کاملRevisiting the theory of the evolution of pick-up ion distributions: magnetic or adiabatic cooling?
We study the phasespace behaviour of heliospheric pick-up ions after the time of their injection as newly created ions into the solar wind bulk flow from either charge exchange or photoionization of interplanetary neutral atoms. As interaction with the ambient MHD wave fields we allow for rapid pitch angle diffusion, but for the beginning of this paper we shall neglect the effect of quasilinear...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001